Electrical plug



. Patented Feb. 14, 1933 bodiment of the plug,

UNITED 'STATES JOHN E. IOOBHOUSE, -OF BOCH'JEBTER, NEW YORK, ASSIGNOR,BY RESINE ASSIGN-` PATENT oFFlcE EENTS, OF ONE-HALF TO SALVATORECONDELLO, OF ROCHESTER, NEW YORK ELECTRICAL PLUG Application illed Iarch9, 1929, Serial No. 345,625. Renewed January 27, 1932.

This invention relates to an electrical plug such as is used, forexample, to connect the -cord of an electrical lamp or electricappliance of any kind to a socket supplied with electric current. Theprincipal object of the invention is the provision of a simple andsatisfactory plug which may be used either with a screw threaded socketor. with a socket of the prongreceiving type.

Another object of the invention is the provision of a satisfactory plugso constructed that it may be inserted in a threaded .socket by astraight longitudinal motion, without rotating the plug andconsequentlytwistin the cord to which it is attached, and whic will be firmly andsatisfactorily held in the socket when it has been thus inserted.

To these and other ends the invention resides in certain im rovementsand Vcombinations of parts, all) as will be hereinafter more fullydescribed, the novel features being pointed out in the claims at the endof the specification.

In the drawing: Fig. 1 is a side elevation of a preferred emillustratingit ready for use with a threaded socket;

Fig. v2 is a side elevation showing the lug ready for use with a prongreceiving soc et;

Fig. 3 is a sectional viewvtaken longitudinally through thecenterof theplug, showing the prongs twithdrawn so that the plug ma be used with athreaded socket;

. 4 is a view similar to Fig. 3 showing the prongs in position tocooperate with a uprong receiving socket;

F 1g. 5 is a transverse section substantially on the line 5--5 of Fig.3,A showing the threaded portion of the-socket in expanded positron,

Fi 6 is a view similar to Fig. 5 showing the rea ded, portion contractedso that the plug may be inserted longitudinally in a threaded socket,and

Fi 7 is a perspective view of a closure inem r and a pair of electricalconductors.

Similar reference numerals throughout the several views indicate thesame parts.

The novel provided. When the plu p ference of the socket, there beingplug comprises a` body -10 of suitable Ainsulating material suchV ashard.

rubber or the like, and has 11 extending axially of the body, and openacentral cavity ing into a slightly larger cavity 12 at the lower endthereo The upper end of the Vbody/has a shape .which is somewhat spiral1n cross section, as illustratedmost clearly in Fig. 5, and around thisspiral portion there is an arcuate metallic member'l which has screwthreads formed thereon of the proper socket. `The threaded member iswith a handle 15 near the free end o er edge thereof, and is made ofmetal is sujiiciently resilient so that this handle may be movedrightwardly to collapse or Provided the lowcontract the threaded member13 toa smaller diameter, as illustrated in Fig. 6. When the diameter ofthe threaded member is thus contracted, it is suiiciently small so thatit may be inserted in a standard threaded socket by a straightlongitudinal motion, 'thout turning the plug. The dot dash cirglle 16 inFig. 6 illustrates diagrammatically the position of a threaded socketwhen the contracted threaded member of the plugI is bein inserted intr.lit, and illustrates the ample c earance has been thrust longitudinallyinto the soc et, the contracting handle 15, is thenvreleased and theresilience of the threaded member 13 causes it to expand, resuming thearcuate shape shown proper diameter to en gage snugly with the threadsof a threadedl which I 1n Fig. 5, so that it engages effectively and I'of a socket, it would come in the-socket and is prevented from wobblingin any direction.

To enable the plug to be used with a prong receivingr socket as well aswith a threaded 5 socket, a slide member 2O is movably mountj tocooperate with a standard prong receiving socket, and they extendthrough slots .in the body- 10 of the plug, sothat when the slide member20 is moved upwardly within the cavity 11, the prongs will be projectedfrom the end of the plug as shown in Fig. 4. When the slide member 20 ismoved downwardly to the position shown in Fig. 3, the prongs a-re thenwithdrawn so that their ends are substantially flush with the end of theplug, Aor even somewhat within the plug.

A closure member 25, of the shape best shown in'Fig. 7, ts within theenlargement 12 at the lower end of the plug and serves to close thecavity 11. This closure member 25 is also of insulating material, andcarries two upwardly extending conducting members 26 and 27 which liealong the sides ofthe cavity 1'1 and in contact with the prongs 21 and22, respectively. Thus the prongs'have a sliding electrical contact withthe conducting members so that in all positions of the prongs they areelectrically connected to these members. The conductors 26 andy 27 areconnected at their lower ends to wires 28 and 29 respectively whichextend out through openings 30 in the closure member 25, and which leadto the lamp or appliance to which it is desired to furnish current. Theclosure member 25 is held in place by a pin 31 which passes through thismember and through the ody 10 of the plug.

A central contact 1s provided on the plugl to cooperate with the centralcontact of a.

This central conby a strip of metal standard threaded socket. tact ispreferably formed having a portion plug, which portion the body, so thatthe portion pressed sli htly by contact with the cooperating part of thesocket. The strip of metal of which the portion 35 'is formed extendsdownwardly at 37 alongside of and in contact with they prong 21, and theextremity of this strip is bent upwardly at 38 so that it is locked tothe body of the plug. The sliding contact between the strip 37 and theprono' 21 thus provides tion lbetween the central contact I35 of theplug and the prong'21 at all times, and sinc'e this prong is alwayselectrically connected to the conductor 26'and to the wire 28, it

overlies a recess 36 in follows that the central contact 35 is alwayselectrically connected to the wire 28.

An electrical connection between 'the other 35 at the upperend of the 35may be de- Y left hand side of an electrical ',connec- A wire 29 and thethreaded member 13 may be provided by a pin 39 passing through the wallof the plug, one end of the pin being connected to the threaded member13 and the other end thereof being in Contact with the conductor 27, asshown in Figs. 3 and 4.

For shifting the prongs 21 and 22 back and forth from an effective to anineffective position and vice versa, and also for shielding the threadedmember 13 when the plug is being used in connection with a prongreceiving socket, there is provided a sleeve 40 arranged to slidelongitudinally on" the body 10. Slots 41 are provided at diametricallyopposite points in the walls of the cavity 11 of the plug, sleeve 40,the slots 41, and the slide member 20. Thus any motion imparted to thesleeve 40 in a longitudinal direction is transmitted to the slide member20, and the prongs 21 and 22 may easily be projected or withdrawn simplyby grasping the sleeve 40 and Vmoving it longitudinally in one directionor the other. When the prongs are projected, as in Fig. 4, the sleevemember 40 surrounds the threaded portion 13 of the plug, preventingaccidental contact therewith, thesleeve member being of insulatingmaterial. When the prongs are withdrawn to an ineffective position, asin Figs. 1 and 3, the sleeve 40 Vis withdrawn from the threaded member13, so that the latter may be inserted in a vthreaded socket.

and a pin 42 passes through the A slot 43" is provided in the sleeve 40in position to receive the handle 15. Preferably this slot is so placedthat the handle 15 must be brought to the position shown in Fig. j

atively thereto to the bottom of the slot, to

the position shown in Fig. 2. When the handle 15 is then released, theresilience of the member 13 will tend to move this handle left'wardly sothat it will pressagainst the the slot 43, thus frictionally engagingthe sleeve 40 and holding it frictionally in its upper position. Whenthe sleeve is shifted to its lower position to with# draw the prongs,the handle I15 normally overlies the sleeve as shown in Fig. 1, and thuslocks the sleeve in this position. It is apparent that thevprongs cannotbe projected to an effective position until the threaded member 13 hasbeen contracted, and thus it is practically impossible to project the'has been disclosed, it is to be understood that l 4. n electrical plugthe wires 28 and 29 attached, my. then beinf serted in the end of theplug an the pins 31 put ifn laceto hold the parts in this position. hi eone embodiment of the invention the inventive idea/may be carried out ina number of ways. fore not to be vlimited to the precise details shown,bu t.is intended to cover all .variations and modifications thereoffalling within the spiritof the invention or appendedA claims.

I clamas my invention:

1. An electrical plug comprising abody having a screw threaded portionto coo erate with a threaded socket, a prong mem er to cooperate with aprong receivingsocket, said prong member being movable from aninefective to an effective position, and a guard member` for thescrewthreaded portion, said guard member bein' controlled by movement ofsaid prong meme 21 An electrical comprising a body h 'a threaded socket,movably mounted relative arranged to be projected to tion to cooperatewith socket or retracted to an ineffective position substantially withinsaid body, and a movable shield arranged to surround said threaded.portion when said prong member is in an eiective position and to bewithdrawn from said threaded portion -when said prongmem` a prong memberto said body and an effective posia prong receiving termined size, 'aandan actuating member 5o mounted on said threaded portion for moving onepart of said threaded portion in a generally circumferential directionrelative to another part thereof to collapsesaid portion to a diameterless than theinternal diameter in said socket by asti-aight'longitudnalmo- 1on. w n

comprisin .al bod having a screw threaded g y -ate with a.' threadedsocket, said. threaded portion comprising a formed in an` arc of acircleand provided with threads for cooperation with thethre'ad's of asocket,1neans forholding'one part of 5 s aid member substantially fixed,and means the scope of the r is moved to an inefective position,so thatIresilient member This applicationis therer Plug avmg a screw threade4portion to cooperate ceiving socket, said connected to said memberadjacent one end of the arc thereof for moving suchend in acircumferential direction to change the diameter of said arcuate memberso that it may be inserted in said -socket by a straight longitudinalmotion and may be retained therein by engagement of the threads of saidthrladed portion with the .threads ofsaid soc et.

5. An electrical plug'comprising a body having a screw threaded portlonto cooperate with a threaded socket, said threaded portion being soformed that it may be 5ontracted to a diameter 'less than the diameterof the socket with which it cooperates, means for contracting saidthreaded portion, a prong member for cooperation with a prong/,Cre-

movable from an ineffective position to an` eii'ective position, andmeans interlocking said prong member with said contracting means .Sothat said prong member may be moved toV effective position only lwhensaid threaded portion is contracted.

GnAn electrical plug comprising a body having a cavity and a screwthreaded por-Kl tion to cooperate with a threaded socket, a. pair ofelectrical conductors within said cavity, a pair of prong membersslidably mounted for movement to a `position projecting from said b`odyto cooperate with a prong receiving socket or to an ineiiective positionsubstantially within said body, each of said prong members being insliding contact with of a threaded-socket so that it may be inserted,

portion 4to cooperone of said electrica-l y conductors, an electrical-Lconnection between said screw threaded portion and one of saidelectrical conductors, a central contact to cooperate with a centralcontact .of a threaded socket, ard a sliding contactconnection" betweensaid central contact and one of said prong members.

7. An electrical having a central cavity' and a screw threaded prongmember l being plug comprising a body portion 1to cooperate with athreaded socket,

a sliding member mounted for movement within said cavity, a air ofprongs mounted onsaid` sliding mem er and movable therewith, said prongsbeing movable to an eective position ,proj ecting from said body toco-Joperate with Za. prong receiving socket and being movable to anstantially within said body, a closure member, and a "pair of electricalconductors mounted on said closure member and extending into saidcavity, said"`electrical conductors `forming Velectrical 4connectionsfor said prong members.4 Y Jol-INH. Moolnfrousia;`

ineffective positionsub-

